Efforts to manage stormwater overflow from Cypress Creek to Addicks Reservoir continued late October when the Harris County Flood Control District submitted draft reports of recent study findings to the Texas Water Development Board.
HCFCD presented details on two plans at a public meeting in September and spent the next 30 days compiling public comments. A grant awarded by the TWDB in 2012 was used to conduct the study to come up with the best plan.
Flooding concerns revolve around storms that cause Cypress Creek to overflow and that overflow making its way to Addicks Reservoir. Although floods in the area do not occur often, HCFCD is looking to prepare for future development in west Harris County, which is expected to make flooding more of an issue.
"The reservoirs have very large capacity, but the capacity is limited," said Dena Green, study manager in HCFCD's engineering and construction division. "If too much water is released, it can impact the folks living downstream along Buffalo Bayou. If not enough is released, it can affect those upstream of the reservoir."
Projections from the Region H Water Planning Group show the population in the study area rising from 312,000 people to around 550,000 people by 2060. Green estimates 30,000–40,000 acres of land will be developed to support that population.
Both concepts employ a combination of storage and conveyance components, said Burton Johnson, a consultant working on the project. They were both developed with the concept of probable maximum precipitation in mind—the statistically plausible worst-case event from the standpoint of a fully developed watershed.
The Mound Creek plan involves building a reservoir for storage at Mound Creek with collection channels to funnel overflow to Bear Creek, which would be widened. The Katy Hockley/North Cypress plan involves creating a larger storage area around Cypress Creek.
The Mound Creek plan uses less land with a greater inundation depth, features a shorter drain time and is estimated to cost $271 million. The Katy/Hockley plan, which is estimated to cost $369 million, provides more storage, could create more conservation land and has a greater opportunity for financial contributions from partner organizations based on early funding studies.
In a separate but related initiative, HCFCD is preparing draft development guidelines for overflow management. These proposed recommendations will be submitted to Harris County Commissioners Court for consideration.
Once approved by TWDB, next steps involve getting approval from the Commissioners Court for the Regional Overflow Management Concept Plan. Following approval, HCFCD officials will investigate further into funding strategies before submitting a final report to TWDB in the first quarter of 2015.
